Resilient wheel mounting



' May 4, 1943. T. A. PETERMAN 2,318,257

RES ILIENT WHEEL MOUNTING Filed May 3, 1941 '7 Sheets-Sheet 1 I r IIIlI/IIIIIIIIIllIllIIIIIllI/fl INVENTOR 7/76000/"6 A. Pe/erman ATTORNEY -May T. A. PETERMAN RESILIENT WHEEL MOUNTING Filed May 3, 1941 I 7 Sheets-Shea: 2

BY Z

'ATTORNE S May .4, 1943.

T. A. PETERMAN RESILIENT WHEEL MOUNTING 15 I i 14 9 i4 5 f7 46\ 4Z6 4Z\ 4 1 4/: a? =45 F 4 45 I '47 INVENTOR Theodore A. Pe/erman dub I I ATTORN Ys May 4, 1943. -T. A. PETERMAN 2, 8,

qIRESILIENT WI-IEEL MOUNTING Filed May 3, 1941 7 Sheets-Sheet 4 INVENTOR Theodore Ape/armor;

' ATTORNE s May 4, 1943- T. A. PETERMAN RESILIENT WHEEL MOUNTING Filed May 3, 1941 '7' Sheets-Sheet 5 n u I I YINVENTOR Them/are A. Pe/e/"mam BY- 4 V r M I w r ATTORNES V T. A. PETERMAN 2,318,257

0 RESILIENT WHEEL MOUNTING I Filed May 3, 1941 7 Sheets-Sheet '7 May 4, 1943.

INVENTOR Theodore/Lfe/ermarv WWW/M4 ATTORNE 5 Hun Patented May 4,1943

,313,257 V RESlLlENT Momma V TheodoreA. Peterman, Tacoma, Wash. Application May 3, 1941, Serial No. 391,668

-8 Claims.

My invention relates to suspension systems, and particularly to resilient mountings for multiplewheel truck and trailer units.

The transportation oi. heavy loads over rough terrains presents problems not encountered too. similar degree in hauling on smooth highways.

- An example of such service is found inthe log ing industry, where huge clogs must be carried out of the forests over trails and unimprovedroads to the saw mills. The dictates of economy require that such loads must be carried at substantial velocities, and the suspension systems used must be suitable for high speed hauling on paved roads wherever they are available; 7 b

The latter requirement practically eliminates track-laying vehicles from consideration, and makes it desirable to use a plurality ofwheels to distribute the weight of the load over a larger area. of the road surface. Each wheel unit must 7 be resiliently connected to the load carrying frame independently of the other wheel units for smooth hauling. Such independent suspensions utilizing conventional steel springs and multiple bearings have been unsatisfactory in service. The springs required are cumbersome, making the unsprung weight ratio unfavorable. Lubrication and maintenance of bearings have been expensive and tlmeconsuming, and the initial expense excessive.

The present invention makes use of rubber mountings in certain preferred forms which will be set forth hereafter. The arrangements shown provide a compact, light, and convenient individual suspension for each wheel unit. Q'I'he problem of lubrication is eliminated, maintenance is reduced to a minimum, and the entire suspension unit may be quickly replaced when desired.

In my embodiments, as set forth below, the un structure of one of my resilient suspension units;

'(CL 280-124) n V tion line 2-2 of that figure, and' jpartially in'section the embodiment'of Figure 1; I I

Figure 4 is a sectionalview, taken as indicated by arrowsJ-t of Figure 3, showing in detail the Figure 5 is a top sectional view of the suspension unit of Figure'4', taken as indicated by line 5-5 of that figure;

Figure 6 is an end sectional 6-6 of that figure;

Figure 7 is a sectional viewcbflespondirig to Figure 8 is a view, partially in section, taken in l the direction indicated by arrows 8-8 of Figure 1, showing the connection between the'walking beam and each wheel pair;

Figure 9 is a top View of an eight-wheel. supporting unit embodying another preferred form of my invention, taken in plane 9--9 of Figure 10;

b Figure 10 is a plan viewer the embodiment shown in Figure 9, taken as indicated by the ar-,-

rows lfi-JB of that figure;

Figure 11 is a side view oi the embodiment of 7 Figure 9; b V

Figure 12: is a side view, partially in section,

" taken as indicated by line 22-42 of Figure 1c toshow in detail the construction of the resillent suspension unit embodied therein;

sprung'weight is greatly reduced, which is of ac knowledged advantage in reducing wear and tear on the highways, while the truck operator benefits by considerable savings in the first cost as well as in upkeep. 7

These and other advantages will appear to those skilled in the art from the following description, and from the drawings, in which I have v illustrated the preferred embodiment of my invention.

In the drawings: V

Figure 1 is a top view of an eight-wheel supporting unit embodying a preferred form of'my invention, taken in the plane of line i-i in Fig- Figure 2 is aplan view of the embodiment shown in Figure 1, taken as indicated bythe sec- Figure 13 is a view corresponding to that of Figure 12,- but illustrating the suspension unit in a flexed position corresponding to that occupied when the wheels assume a tilted position such as that indicated by the dotted outlineiri Figure Figure 14 is a top view of an eight wheelsupl porting unit embodying still another" preferred form of my invention;

v Figure 15 is a vertical section of theembodiment shown in Figure 14, taken as indicated by the arrows i5i;5 of that figure; V

Figure 16 is a side view of the embodiment of Figure 14; i

Figure 17 is a sectional view, taken as; indicated by line ill-41 of Figure 16, showingin detail the construction of the" resilient suspension unit incorporated in Figure 14; and

Figure 18 is a side sectional view, taken as; I

indicated by line l8-i8 of Figurel7, of the sus- P nsion unit detail. a b

Figure 3 is a side'view, partially in section, of

Directing attention now to Figures 1 and 2 of the drawings, I have shown aneight-wheel trailer unit, generally denominated as I, which is joined to a suitable motor-driven unit, not shown, by connecting member 2. The load is carried directly on a bunk 4 supported on a bolster 5. B01- ster 5 extends transversely from the connecting member 2, and has at each end thereof resilient mounting units 6 to which are attached equalizer or walking. beams 1 extending parallel to the connecting member 2. At each end of each walking beam 1 is formed a'hub 9 to which a pair of wheels I is connected. The details of the mounting in hub 9 is shown in Figure 8, and

y will be described hereaften.

The bolster may conveniently be formed with a tubular central section II, to either end of which is secured a rectangular socket l2 in which the resilient mounting unit 6,.hereinaiter called simply the cushion 6, is held. Socket I2 is open on the bottom, and at the outer end is closed by a removable end plate l4 held in pocushion unit inthis fashion, it will be apparent,

that the weight of. the load will betransmltted eition by suitable means such as bolts I5. The

cushion unit 6 issecured in socket l2 by a plurality of bolts I6 threadably inserted through side walls ll of the socket l2 and into steel casing i9 01 the cushion 6 g The details of the cushion unit 6 and the manner in which itrrockably' attaches the walking beam 7 tothe bolster ll will next be considered. This rockable connection permits the front and rear pairs of wheels Hi to accommodate themselves in turn to inequalities in the road surface. producing a vertical displacement of the bolster which is only half that which would be'experienced if a single set of wheels were 'used on each side or if beam 9 were not permitted torock.

Each of the cushion units 6. comprises 9. recta. gular, steel casing l9 open at the bottom, and

of proper size to fit snugly within socket i2. Within the casing I79, and bonded thereto bymeans well known in the art. is ,a compression block; 29011 rubber, which carries the. vertical load, and a torsion block 2|, likewise of'rubber, I

vides for rocking of beam 1. r v

A comparison ofl igures 6 and 7 will .indicate the manner in which the torsion block 2i deforms from the normal when stress is applied to tilt the pairs-oi wheels attached to walking beam 'i cut of alignment parallel to the line of travel of the trailer unit I, as for example when the ."ieels are rocked into one of the dotted line reel positions 22. or 24 (Figure 3) 'by inequaliint-he road surface. The compression block 20 is substantially recwhich carries the horizontalstressesand protangular in outline, and is pierced vertically by H plurality of apertures 25 aligned in a single row centrally of the block. The purpose of thesev apertures 25 is dual; toprovide space for, the deformation of the rubber under load, and to permit the insertion of a plurality of bolts 28 through a rectangular steel load plate 2'! bonded to the underside of the block 20. The load plate "extends across the full width of the block, but shorter than the casing 'l9,'so thaten'cl por- 2? overhang the plate 21. The under sur- :face 29 of end portions 21 may be sloped upsrdly from the plate 21 to the end walls '30 of easing iii to reduce the amount of rubber re quired. v

Bolts iii are used to secure load plate Tito a re tangidar column 31 which is bonded to. and

cm was bu lower load plate 32 is bonded'to the under sure nds centrally through, the torsio nhlock 2| '7 cured to hubs 4'1 by the face of torsion block 2|, and is apertured to permit insertion of a row of bolts 34 for connection to column 3| of a webbed bracket 35 extending upwardly from the walking beam 1. The under surface 36 of that portion of torsion block 2! overhanging the lower load plate 32 inclines upwardly toward the casing is. In assembling the imately coinciding with the center line of the upper load plate 21, whiletorsion block 2| deforms to cushion the movement. The action during deformation, shown in Figure 7. is such that a portion of block 2| acts in tension, while the remainder is under compression. The direc-. tion of the rockingmovement is-immaterial, and the effect is one of rapidly damping the movement about axis 31; Lateral thrusts. are absorbed by the end portions 38 of the torsion block 7 The walking beam 1 maybe of hollow rectanggular section, with the webbed bracket 35 formed centrally thereof and the hubs 9 formed at each end. The hub 9 is a cylindrical member mounted transversely. of the beam 1, and may be conveniently formed integrally therewith by welding. ,An axle 40 is mounted rotatably within hub 9 by means of thrust bearings 4| disposed at either end thereof and held'in position by suitable thrust washers 42 andlock nuts 44 threaded onto axle 40 at 45. Conventional lubricant- -retaining seals 48 are inserted in the ends of hubs 9. Wheel'hubs 41 are fixed on axle 40, with brake drums-49 extending inwardly'therefrom, by meansof locked nuts 48. Conventional disc wheels 50 carrying tires 5| are removably seusual means, such as bolts 52.

Within brake drums 49 is secured brake lining 53, which is engaged to produce braking action by brake shoes mounted on brake hub 54.' The brake shoes and actuating mechanism therefor have been schematically illustrated at 55 attached to the brake hub 54, which is in turn secured to hub 9. The braking mechanism is protected from dirt by a flanged closure plate 56, also secured to hub 8 The details of the braking mechanism forin no part of the presentinvention, since 'many satisfactory forms are known in the art. v

Returningnow to Figures 1 to 3 of the drawings, a webbed casting is shown securing the connecting member 2 to the bolster 5 and maintaining the alignment of the latter rigidly n0rmal to the former, and in addition providing vertical reinforcing for the bolster. In the logging industry, for which the illustrated trailer embodiment trailer service where very long loads are carried, provision must be made for curves in the roads, and the load must be allowed some freedom to turn in a horizontal plane relative to the trailer unit. Hence,the bunk 4, on which the load is carried, is Joined to bolster 5 centrally by a pivotal coupling 6|. A resilient block 62 is mounted in bolster 5 over each cushion unit 8, and has secured to the upper side thereof a smooth rounded end engaging plate 64 which extends parallel to walking beam 1. The bunk 4 restson plates is designed, as in any 64, so that the load is evenly distributed over the bolster. The sliding contact between plates and bunkl allows the bunk to turn on pivotal "coupling GI and still be supported by each end of the bolster as well as by thecentral coupling.

From the above description it'will be obvious to those'skilled in the art that my invention is a compact, light, suspension'un'it which requires very little attention, but which can be removed with a minimum of time and expense. The design permits the tandemomoun'ted paired wheels on each side of the trailer to accommodate itself to road inequalities without reference to those on the opposite side. Further, the front and rear wheel pairs of each wheel unitencounter 'each particular obstacle separately, and the vertical load displacement resulting is halved by theiwalking beam mounting. Lateral thrusts, as well as those parallel to the direction of motion, areabsorbed by my suspension unit, 'an'd'the rubber 'In Figures 9 to 13 of the drawing 5,1 have set 'forth another preferred embodiment of my invention utilizing rubber cushioning members, and pairs of wheels tandem-mounted on an equalizer beam; The trailer unit, indicated generally as IN), is joined by a connecting member! to the motor truck or other source of tra'ctive power, not'shown.

The structure herewith illustrated is particularly designed for handling long heavy material,

ster, while the bunk 4 is supported centrally, on

thefbolster frame 65 by'means of a.-pivotaljoint xi I, and at each end thereof by upwardly extending columns 63 having engaging plates 54 fixed thereon. Engagin plates 64 are elongated parallel to connecting member 2 and terminally rounded, andthe bunk-4 rests slidably thereon.

This permits the bunk '4 to rotate in a horizontal plane about the pivotaljoint s I, so that the load,

which is rigidly. secured tothe bunk, can be carried-around corners and curved roads. 7 At either end of the bolster 65 are fixeda pair of resilient suspension members maligned axially of the bolster. Between each'pair of suspension members .10 is mounted a'bracket arm ll formed integrally with a walking beam 68, and reinforced by webs 12 connected thereto. Walking beam 68 extends parallel tolthe connecting member 2 and transversely of bolster 65, and has hubs 9 formed at each end thereof to which pairs of wheels III are connected by means described in detail in connection with Figure :78.

Each of the suspension members 10 comprises a cylindrical housing 13 extending downwardly from bolster 65 and secured thereto rigidl y by rounded head 80 formed on the upper endof a load-carrying-columnji axially disposed within housing '12 Column "'81, "extends downwardly from 'the casing 13 and is rigidly secured to the walking beam or e'qualizer 68, passing through a bored bossi l z' formed :te'rn'iinally of the walking beambraclg'g ll beingthreaded at 84 to receive a castellated lock-nut 85. -Lock washer, 86 and cotter pin' B'I may be used to prevent loosening of the connectiombetween column- 8| and the walkingbeam il. Allthe vertical load components .are'carried iii-compression by the compression block 15, and transmitted thereby through the column 8| to the walking beam .68 and thence 'to the wheels [0, It -w'ill'be seen-by an inspection of Figure '13, which shows the action of the I suspension member :10 during rocking or tilting of the walking beam- 68, that the rounded head ail-0f ce luinn l l e'n' ib s theannularplate 19 on cushions provide a smoother haul with rapid damping efiects.

compression block 15 in :proper stress-transmitting positionregardless of the twisting of column 81 out of the normal-vertical alignment.

7, Within housing 13 and surrounding the column 81 is an annular torsion 'block 89, also formed of rubber or similar resilient material.

The torsionlblock 89=is bonded within a cylindrical shell 90 which makes a smooth sliding'flt within housing 13. Azcentral cylindrical sleeve 8| is bonded within'the block 89 andfits snugly around column fll. The rounded head '80 presses the central cylindrical shell tightly against the walking beam bracket boss]! when lock nut 85' is tightened, so that the torsion block 89 holds the whelsand walking beam against forces tending to pullthe column-M out of the housing, 13.

The torsion block is itself held in position within housing 13' by an annular locking cap 92 welds 14 or equivalent means. Within housing 13 is" fixed a compression block 15, cylindrical in.

pressio'nblock 15.. c V g Those skilled in the artiwiila'ppreciate that the resilient mounting ,sh'ownprovides a compact, 'light rsuspension which combines vibration and controllingsidesway, I p 7 7 No lubricationis required ,tor the proper iu'n'ctioning-of, my suspension unit,; and whenit is de- 5 .threadably joined to the lower end-ofthe hous- 7 ing at 91 and Ien'gaf'ging the cylindrical shell 90. 1

Shell is'tig'htened by cjap'llz 'against an annular shoulder projecting inwardly from the upper portion'of housing 13. s and cushions the horizontal force componentsincident to'h'auling the load,-and at the same time allowsthe walking beam to rock as the wheels l0 encounter irregularities in'the road surface. The Y dottedwheel outlines 24 and]! in Figure 11 lllustrate'the wheel positions during such rocking, and the approximate center about which the rocking occurs isshown at96 inFig'ure 13. It will be observed that the use-of the walking beam connection between. wheels and bolster-frame results in a vertical displacement ofthe latter, and;

consequently of theload, amounting to only onehalt the displacement of each wheel. Hencethe load is carriedrnore smoothly by the suspension system shown than ispossible in conventional wheel mountingsregardless ofthe type of spring mounting. Itiwillalso'be seen-that the torsion block 89 acts as alcheck against recoil, so that the unit 'Hicombines the functions of a spring suspension, a shock absorbing, I and acoil damping'system. It will alsobe obvious that .the torsion block is'eflective'in absorbing lateral thrusts sired. to;take;it apart ioi inspection or replacement it is only-necessaryito unscrew; the cap 92. 7 I Torsion block then slides out freely, and late '16 may be turnedto-permitreme .-'al ofthe com-' Torsiomblock 89 absorbs loaded on and fastened to the'bunk I05.

:the axis of the bolster;

damping and shock absorbing functions, with side sway control. The lubrication problem is eliminated, and maintenance reduced to a minimum. 1

Figures 14 to 18 of the drawings illustrate a further preferredfform of resilient suspension mounting of my invention. Here the entire --tra'iler unit, indicated generally'as IOI, comprises the wheels I0, the walking or equalizer beams I02 to which the tandem mounted pairs of wheels are directly connect'ed,-the bolster frame I04, and the connecting member 2 which joins the trailer unit IOI to a truck or equivalent source of motive power, not shown.

The embodiment shown was designed with particular reference to the logging industry, in which 'long heavy trees must be transported after felling to the sawmill. The logs are secured to the truck at the front end, and the rear ends are wheels and: the bolster frame are held in flired relation to the connecting member 2 by a webbed reinforcing :member I06. It is necessaryto provide a pivotal connection between bunk I05 and the bolster frame I04,'-in order that curved roads and corners may be negotiated with. the long loads fixed on the trailer bunk I05. 'Hence a pivotal center joint I01 is used, while near each end of the bolster a supporting member I09 extends upwardly'therefrom and is topped by an elongated plate 04 on which the bunk I05 may rest in slidable engagement. When the bunk I05 turns on pivot I06, the load is still supported at the outer ends of the bunk by the elongated plate 64.. The plate is-rounded off at'its ends I I to prevent catching. against bunk I when executing very sharp turns.

A pair of spaced bolster arms I II extend downwardly from each end of bolster I04, and are arranged to receive the cushioning units at their lower ends. Each bolster arm hasa half-round lower end II2, with bosses II4 bored to receive bolts us. Bolts n5 pass through bored bosses II8 formed on a half-round cap I". Ribs H9 are provided to strengthen the bolster arm lower .end H2, and similar ribs 'I20 reinforce .cap Ill.

' hub I30 may bejoined by any convenient means,

such as welds III. p

The walking beam hub I 30 and the beam I02 formed integrallytherewith carry wheel pairs I0 fixed to each end of the beam I02 through hubs 0. The details of this hub structure were described in, connection with Figure Band will not be repeated here. V

It will be seen that the cushion members I2I are adapted to absorb lateral thrusts, and both horizontal and vertical components of load stress. It is intended that the cushion members are to be bonded .to the cylindrical shaft I25, so that the rocking movement of the walkingbeam I02 maybe controlled thereby. InFigure 16 I have shown in dotted outlines 22 and 24 the positions assumed by the wheels I0 at substantially the limits of their torsional movement about shaft This structure is shown in sectional view normal i to bolster I04 in Figure 17, while in Figure 18 I have shown the details of eachspac'ed pair of bolster arms III -in-a sectional view "parallel-to The half-round lowerend'IIZ of'bolster arm III combines with the half-round capI II to form a round seat for'the tubular cushion block I2I,

' formed of rubberor similar material. From Figure' 1'] it will be seen that while the seat thus formed is circular in section throughout, both half-round portions taper inwardly toward the opposite arm III, so that the seat I22 is frustoconical. Cushion blocks I2I are formed with cylindrical bores I24 axially thereof, and are outwardly congruent with the frusto-conical seats I24, thus acting in fashion similar to' tapered thrust bearings. A portion I23 may be cut flat to provide clearance for bolts Il,5.g r

-A cylindricalshaft-"I25 is inserted through the cyiindri'calboresIH of. the cushion blocks I2I, and-secured in place'by lock nuts I26 engaging threaded shaft ends I21. The'1ocknuts'I26 place off blocks I2I' under any desired compression.

through washers I28 disposed therebetween.

Shaft I 25 also passes centrally through the w alking beam. hub I30, fixed thereto between 'the I25.- It has been observed that the rubber mem bers I 2| cushion the initial shock of rocking motion of beam I02, and dampen the oscillations thereof rapidly. The use of the walking beam wheel suspension permits each pair of wheels I0 to encounter road irregularities with a resultant vertical load displacement substantially half that which would be experienced with the usual wheel mounting. This is of great advantage in making possible higher speeds in hauling and in reducing the strains on the entire supporting structure. 7

The'embodiment illustrated in Figures 14 to 18 is compact, light in weight, and free from lubrication and maintenanceltroubles. If it is necessary to removethe wheel assemblies from the trailer, it is only necessary to loosen bolts I I5 and similarly in case it is desired to replace. the cushion blocks I2 I in'road surface is obtained, and faster, smoother hauling, with resultant economy of operation. A reduction'in the first cost of the spring units is obtained, while themorefavora'ble ratio of sprung to unsprarg; ageight results in less dam age to highways in hauling heavy loads at high speeds. I j V V Modifications in'the details of my' structure may occur to those familiar with the art. and it will be obvious that the principles of my invention may be applied to services other than that for which these embodiments were particularly designed without departing from the spiritof the: invention claims. I claim:

1. m a vehicle, a frame, a plurality of wheels tandem-mounted on walking beams, and a reas set forth in the appended siiient suspension unit joiningeach'of said beams to said frame cor'nprising a housing, a. resilient load-supporting member disposed therein, and

paired bolsterarms I I I andengag'ed laterally by cushion b1ocks"I2I.'- The walking beam 102 and a secondiresilient member disposed therein'jar- .ranged-to absorb'horizontal thrusts and to cushionto'rsional movements ofisaid' beam relative 'tosaidframe. 3 r

2. In a vehicle having a frame and a plurality of wheels arranged in tandem on equalizer beams,

resilient suspension units connecting each of said beams to said frame, comprising a hous-i ing, a resilient load-carrying member positioned therein, and a resilient thrust member posi- 2,s18,gt7 I transversely from each of said walking beams and securedto said columns from each pair of said housing members. 1 6. In a multi-wheeled vehicle-having a frame and walking beams joining pairs of said wheels in tandem, resilient means for supporting said tioned therein and arranged to permit both lonbolster, a resilient supporting unit removablyfixed within said seat and connected to said beam and including a load-carrying rubber block and a thrust and torsion rubber block.

4. In a vehicle, a frame, walking beams, a plurality of wheels tandem-mounted on said beams, and means for joining said beams resiliently to said frame, comprising a bolster fixed transversely to said frame, a pair of spaced cylindrical housing members extending downwardly near each end of said bolster, a compression block disposed within each of said housing members and bearing against said bolster, a rigid column positioned axially of said housing and bearing upwardly against said block, an' annular torsion block disposed about said column and bonded to said column and within said housing, and bracket arms disposed parallel to said bolster joining frame on said beams, comprising bracket arms extending transversely centrall'y'of said beams,

supporting columns extending vertically from said bracket arms on each side of said beams, rounded heads formed on each of said columns,

an annular bearing plate engaging-each of said 1 heads, a cylindrical rubber load-carrying block I secured above each of said bearing plates, a second annular bearing plate bonded over each of said blocks; a bolster extending transversely of. 'said frame and resting on said second bearing plates, paired cylindricalhousing members extending downwardly from said bolster snugly about each of said second bearing plates and axially about'said columns, and annular rubber torsion and thrust blocks bonded within said housing membersabout said columns and secured I within said housings.

7. In a rnulti-wheeled vehicle having equalizer: f

beams joining wheel pairs in tandem and a frame, means for resiliently mounting said frame on said equalizer beams, comprisingtransverse bracket arms projecting from said 'beams,=su'p' porting columns extending upwardly from said said columns of each pair of said housing mem bers transversely and secured centrally to one of said walking beams.

5. In a multi-wheeled vehicle, a frame, walking beams securing pairs of said wheels in tandem, and means for supporting said frame resil iently on said walking beams, comprising a hal ster fixed transversely to said frame, cylindrical housing members extending downwardly in pairs from each end of said bolster, a backing plate disposed within each of said housing members in contact with said bolster, cylindrical rubber compression blocks disposed axially of said housing against each of said backing plates, an annular lower backing plate secured beneath each of said blocks, an annular rubber torsion block bonded within each of saidhousing members, a loadcarrying column extending axially through each of said torsion blocks and bonded thereto, a

brackets on opposite sides of each of said beams, a rounded head formed on each of said columns,

an annular bearing platerestingslidably on said head, an annular rubber load block bonded on said annular bearing plate, an annular spacing and upper bearing plate bonded on said load block; a bolster extending fixedly-transversely of said frame and resting on said upper hearing plate associated with each of said columns, a cylindrical housing extending downwardly from W said bolster about each of saidbearing plates and bers and bonded to said column.

columns, and an annular thrust and torsion block secured within each of said housing mem 8. In a vehicle having a frame,

- beams, and agplurality of wheels tandem-mountrounded head formed on each of said columnsand engaging said lower backing plate, and

bracket arms fixed centrally to and extending ed on said equalizerbeams rockably relative to said frame, a bolster fixed transversely of said frame, paired bolster arms extending downwardly from said bolster at each side of said frame, rubber cushioning members disposed in said bolster arms, and shafts extending from said equal- .izer beams into supporting engagement with said l rubber members.

'I'HEODORE A. PETERMAN.

.equalizer 

